<template>
  <div></div>
</template>
<script>
export default {
  data () {
    return {
      sceneUrl: '', // 需要预览的图片绝对路径
      camera: null,
      scene: null,
      renderer: null,
      isUserInteracting: false,
      onPointerDownPointerX: 0,
      onPointerDownPointerY: 0,
      lon: 0,
      onPointerDownLon: 0,
      lat: 0,
      onPointerDownLat: 0,
      phi: 0,
      theta: 0,
      target: new THREE.Vector3()
    }
  },
  mounted () {
    this.init()
  },
  methods: {
    init () {
      let textureLoader = new THREE.TextureLoader();

      textureLoader.load(this.sceneUrl, (texture) => {
        texture.mapping = THREE.UVMapping;

        this.initImg(texture);
        this.render();
      });
    },
    initImg (texture) {
      let container, mesh;
      // 容器宽度、高度
      let containerWidth = this.$refs.container.offsetWidth;
      let containerHeight = this.$refs.container.offsetHeight;
      container = document.getElementById('container');
      this.renderer = new THREE.WebGLRenderer({ antialias: true });
      this.renderer.setPixelRatio(window.devicePixelRatio);
      // this.renderer.setSize(window.innerWidth, window.innerHeight);
      this.renderer.setSize(containerWidth, containerHeight);
      let childs = container.childNodes;
      if (container.childNodes.length > 0) {
        container.removeChild(childs[0]);
        container.appendChild(this.renderer.domElement);
      } else {
        container.appendChild(this.renderer.domElement);
      }

      this.scene = new THREE.Scene();
      this.camera = new THREE.PerspectiveCamera(60, containerWidth / containerHeight, 1, 1000);
      mesh = new THREE.Mesh(new THREE.SphereBufferGeometry(500, 32, 16), new THREE.MeshBasicMaterial({ map: texture }));
      mesh.geometry.scale(-1, 1, 1);
      this.scene.add(mesh);

      container.addEventListener('mousedown', this.onDocumentMouseDown, false);
      container.addEventListener('mousemove', this.onDocumentMouseMove, false);
      container.addEventListener('mouseup', this.onDocumentMouseUp, false);
      container.addEventListener('mousewheel', this.onDocumentMouseWheel, false);

      container.addEventListener('touchstart', this.onDocumentTouchStart, false);
      container.addEventListener('touchmove', this.onDocumentTouchMove, false);
    },
    onDocumentMouseDown (event) {
      event.preventDefault();

      this.isUserInteracting = true;

      this.onPointerDownPointerX = event.clientX;
      this.onPointerDownPointerY = event.clientY;

      this.onPointerDownLon = this.lon;
      this.onPointerDownLat = this.lat;
    },

    onDocumentMouseMove (event) {
      if (this.isUserInteracting) {
        this.lon = (this.onPointerDownPointerX - event.clientX) * 0.1 + this.onPointerDownLon;
        this.lat = (event.clientY - this.onPointerDownPointerY) * 0.1 + this.onPointerDownLat;
        this.render();
      }
    },

    onDocumentMouseUp (event) {
      this.isUserInteracting = false;
      this.render();
    },

    onDocumentMouseWheel (event) {
      this.camera.fov -= event.wheelDeltaY * 0.05;
      this.camera.updateProjectionMatrix();
      event = event || window.event;
      if (event.stopPropagation) { // 这是取消冒泡
        event.stopPropagation();
      } else {
        event.cancelBubble = true;
      };
      if (event.preventDefault) { // 这是取消默认行为
        event.preventDefault();
      } else {
        event.returnValue = false;
      };
      this.render();
    },

    onDocumentTouchStart (event) {
      if (event.touches.length == 1) {
        event.preventDefault();

        this.onPointerDownPointerX = event.touches[0].pageX;
        this.onPointerDownPointerY = event.touches[0].pageY;

        this.onPointerDownLon = this.lon;
        this.onPointerDownLat = this.lat;
      }
    },

    onDocumentTouchMove (event) {
      if (event.touches.length == 1) {
        event.preventDefault();

        this.lon = (this.onPointerDownPointerX - event.touches[0].pageX) * 0.1 + this.onPointerDownLon;
        this.lat = (event.touches[0].pageY - this.onPointerDownPointerY) * 0.1 + this.onPointerDownLat;

        this.render();
      }
    },
    render () {
      this.lon += 0.15;

      this.lat = Math.max(-85, Math.min(85, this.lat));
      this.phi = THREE.Math.degToRad(90 - this.lat);
      this.theta = THREE.Math.degToRad(this.lon);
      this.camera.position.x = 100 * Math.sin(this.phi) * Math.cos(this.theta);
      this.camera.position.y = 100 * Math.cos(this.phi);
      this.camera.position.z = 100 * Math.sin(this.phi) * Math.sin(this.theta);

      this.camera.lookAt(this.scene.position);
      this.renderer.render(this.scene, this.camera);
    }
  }
};
</script>

<style></style>